The closely watched IHS Markit/Cips purchasing managers’ index (PMI) for the sector hit a 37-month high of 57.5 in December, up from 55.6 in November. Any reading above 50 denotes growth.
Analysts said businesses had brought forward orders to beat the end of the Brexit transition period due to finish on December 31 and warned that the sector could decline in the first few months of 2021.
Delays at ports and logistical disruptions meant supply-chain delays also lengthened to one of the greatest extents in the survey’s history, they noted.
Output rose for the seventh consecutive month in December, albeit to a lesser extent than the month before, with growth across the consumer, intermediate and investment goods sectors.
Consumer goods sales had fallen back in November, but the end of the English lockdown and brief reopening of all retailers at the start of December helped it return to growth.
Overall, the amount of stock purchased throughout the manufacturing sector rose to its third-fastest rate in the 29-year survey history, as heavy stockpiling took place.
Rob Dobson, director at IHS Markit, which compiles the survey, said: “Customers, especially those based in the EU, brought forward purchases, boosting sales temporarily. It seems likely that this boost will reverse in the opening months of 2021, making for a weak start to the year.
“Note also that the December PMI data were collected prior to the border closures, which will have led to further logistics and production disruptions for many companies.
“Worryingly, the manufacturing sector was already beset by near-record supply-chain delays even prior to the closure of Dover-Calais shipping.
“Manufacturers reported freight delays – especially at ports – plus shortages of certain raw materials and a lack of supplier capacity.
“Vendor lead times, a bellwether of supply-chain pressures, lengthened in December to a similar extent to during the first wave of the pandemic.”
Business optimism fell back in December, with 56 per cent of manufacturers forecasting output to rise over the next 12 months, compared with 61 per cent in November.